From 99fdafdeacfa99ca9047641b684fa2aaf094a661 Mon Sep 17 00:00:00 2001 From: Jason Cooper Date: Tue, 11 Oct 2016 13:53:52 -0700 Subject: random: simplify API for random address requests To date, all callers of randomize_range() have set the length to 0, and check for a zero return value. For the current callers, the only way to get zero returned is if end <= start. Since they are all adding a constant to the start address, this is unnecessary. We can remove a bunch of needless checks by simplifying the API to do just what everyone wants, return an address between [start, start + range). While we're here, s/get_random_int/get_random_long/. No current call site is adversely affected by get_random_int(), since all current range requests are < UINT_MAX. However, we should match caller expectations to avoid coming up short (ha!) in the future. All current callers to randomize_range() chose to use the start address if randomize_range() failed. Therefore, we simplify things by just returning the start address on error. randomize_range() will be removed once all callers have been converted over to randomize_addr(). Link: http://lkml.kernel.org/r/20160803233913.32511-2-jason@lakedaemon.net Signed-off-by: Jason Cooper Acked-by: Kees Cook Cc: Michael Ellerman Cc: "Roberts, William C" Cc: Yann Droneaud Cc: Russell King Cc: "Theodore Ts'o" Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Catalin Marinas Cc: Will Deacon Cc: Ralf Baechle Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: "David S. Miller" Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H . Peter Anvin" Cc: Nick Kralevich Cc: Jeffrey Vander Stoep Cc: Daniel Cashman Cc: Chris Metcalf Cc: Guan Xuetao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/random.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/random.h') diff --git a/include/linux/random.h b/include/linux/random.h index 3d6e9815cd85..26741892828a 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -35,6 +35,7 @@ extern const struct file_operations random_fops, urandom_fops; unsigned int get_random_int(void); unsigned long get_random_long(void); unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len); +unsigned long randomize_page(unsigned long start, unsigned long range); u32 prandom_u32(void); void prandom_bytes(void *buf, size_t nbytes); -- cgit v1.2.3